What is ICD-10 code C88.90?

C88.90 is the ICD-10-CM diagnosis code for Malignant immunoproliferative disease, unspecified not having achieved remission. A cancer of immune cells of an unspecified type that has not responded to treatment or is still active. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C88.90 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C88.90 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C88.90 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C88.90 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for C88.90?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For C88.90, V28 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors at RAF 0.545 while V24 mapped to Lymphoma and Other Cancers at RAF 0.675. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C88.90?

Use this code only when the specific type of immunoproliferative disease cannot be determined from documentation The fifth character '0' indicates the disease has not achieved remission; document treatment response status Because C88.90 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

C88.90 ICD-10 Code: Malignant immunoproliferative

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupC88.90Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)

C88.90

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Malignant immunoproliferative disease, unspecified not having achieved remission

A cancer of immune cells of an unspecified type that has not responded to treatment or is still active.

Buddy Insight

CMS-HCC V28

Mapped

HCC 21

Breast, Prostate, Colorectal ...

RAF 0.545

CMS-HCC V24

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.675

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.0

RXHCC

Mapped

HCC 21

Hodgkin Lymphoma and Other Ca...

RAF 0.0

Code Trumping

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Code Book Path

Official

C88Malignant immunoproliferative diseases and certain other B-cell lymphomas

C88.9Malignant immunoproliferative disease, unspecified

C88.90Malignant immunoproliferative disease, unspecified not having achieved remission

Inclusion Terms

Official

Immunoproliferative disease NOS
Immunoproliferative disease NOS not having achieved remission
Immunoproliferative disease NOS with failed remission
Malignant immunoproliferative disease, unspecified NOS
Malignant immunoproliferative disease, unspecified with failed remission

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C88.90 in this effective period.

Related Child Codes

Official

C88.91Malignant immunoproliferative disease, unspecified, in remission

Includes

Official

ICD-10-CM does not list Includes notes for C88.90 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C88.90 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C88.90 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C88.90 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C88.90 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Even for unspecified codes, documentation should include available clinical findings, laboratory results, and any pathology that has been obtained.

The reason the specific type cannot be determined should be evident in the record.

Treatment plan, response assessment, and active disease status must be documented.

Provider queries for additional specificity should be documented.

MEAT Support

HCC Buddy guidance

Even for unspecified codes, documentation should include available clinical findings, laboratory results, and any pathology that has been obtained.

The reason the specific type cannot be determined should be evident in the record.

Treatment plan, response assessment, and active disease status must be documented.

Provider queries for additional specificity should be documented.

Audit Caution

HCC Buddy guidance

This is the least desirable code in the immunoproliferative disease category due to its lack of specificity.

Always query the provider for additional information that would allow assignment of a more specific code.

Unspecified codes may be flagged for audit and should be supported by documentation explaining why specificity cannot be achieved.

Common Mistakes

HCC Buddy guidance

C88.91 (malignant immunoproliferative disease, unspecified, in remission) requires documented remission.

C88.80 (other malignant immunoproliferative diseases) is used when the type is identified but does not fit specific subcategories.

C88.00-C88.41 provide more specific codes that should be used whenever possible.

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is C88.90 an HCC code?

Yes. C88.90 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24).

HCC Category Mapping

V28HCC 21, Breast, Prostate, Colorectal and Other Cancers and Tumors

0.545

V24HCC 10, Lymphoma and Other Cancers

0.675

ESRDHCC 10, Lymphoma and Other Cancers

0.000

RxHCCHCC 21, Hodgkin Lymphoma and Other Cancers

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for C88.90

For C88.90to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C88.90 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

C88.90 is the ICD-10-CM diagnosis code for malignant immunoproliferative disease, unspecified not having achieved remission. A cancer of immune cells of an unspecified type that has not responded to treatment or is still active. C88.90 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).

Under the CMS-HCC V28 risk adjustment model, C88.90 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors (HCC 21) with a community, non-dual, aged base RAF weight of 0.545. Under the older CMS-HCC V24 model, C88.90 maps to Lymphoma and Other Cancers (HCC 10) with a community, non-dual, aged base RAF weight of 0.675. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Use this code only when the specific type of immunoproliferative disease cannot be determined from documentation. Because C88.90 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C88.90 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code only when the specific type of immunoproliferative disease cannot be determined from documentation
•The fifth character '0' indicates the disease has not achieved remission; document treatment response status

Clinical Significance

Malignant immunoproliferative disease, unspecified, not having achieved remission is the least specific code in the immunoproliferative disease category, used when neither the type of immunoproliferative disease nor the site can be determined from available documentation. This code should prompt a query to the provider for additional diagnostic information. Active disease that has not achieved remission indicates ongoing malignant process.

Documentation Requirements

✓Even for unspecified codes, documentation should include available clinical findings, laboratory results, and any pathology that has been obtained.
✓The reason the specific type cannot be determined should be evident in the record.
✓Treatment plan, response assessment, and active disease status must be documented.
✓Provider queries for additional specificity should be documented.

Commonly Confused Codes

•C88.91 (malignant immunoproliferative disease, unspecified, in remission) requires documented remission.
•C88.80 (other malignant immunoproliferative diseases) is used when the type is identified but does not fit specific subcategories.
•C88.00-C88.41 provide more specific codes that should be used whenever possible.